Steroids are a class of compounds that share a similar chemical structure. This broad group of chemicals includes many normal substances in the body (such as cholesterol), vitamins (vitamin D), hormones (for example, the sex hormones and their derivatives), and drugs given to treat inflammation (hydrocortisone, prednisone). The adrenal glands secrete a number of steroid hormones, known as corticosteroids, that are important for the maintenance of blood pressure, blood glucose levels, salt and water balance, and other critical body processes. However, when we speak of steroid abuse by athletes, doctors are referring to the misuse of the so-called "anabolic steroids," which are manufactured drugs similar to the male sex hormone testosterone.

The term anabolic refers to the muscle-building properties of these man-made substances. Available legally only by prescription, anabolic steroids are sometimes prescribed by doctors to treat conditions in which testosterone levels are abnormally low, or in certain chronic conditions such as AIDS that are associated with loss of muscle mass. Athletes, bodybuilders, and other people sometimes abuse anabolic steroids in order to improve performance and physical appearance.

Misuse of anabolic steroids is a hazardous practice with wide-ranging adverse effects. Some of the major documented side effects of steroid misuse are:

liver tumors,

high blood pressure,

fluid retention,

increases in LDL (“bad”) cholesterol levels,

decreases in levels of the “good” cholesterol HDL,

kidney tumors, and

severe acne.

Aggression, mood swings, and other psychiatric side effects can also result from the abuse of anabolic steroids.

Along with the general health hazards of steroid abuse, gender-specific effects also occur. Men may experience:

infertility,

reduced sperm count,

testicular shrinking,

baldness,

breast development, and

may have an increased risk for the development of prostate cancer.

Women who abuse steroids have androgenic, or masculinizing, side effects that can include:

growth of facial hair,

deepened voice,

menstrual abnormalities

male-pattern baldness.

For adolescents who have not yet experienced the typical growth spurt, anabolic steroid abuse can result in premature maturation of the skeletal system, meaning that teens who abuse steroids run the risk of having short stature for the rest of their lives.

It is possible to develop a physiological dependence upon steroids. Taking steroid drugs affects the functioning and hormone secretion pattern of the adrenal glands, since these glands are the source of many natural steroid hormones. For this reason, when doctors prescribe steroids, their discontinuation is always tapered (gradually taking smaller doses) to allow the adrenal glands to return to their normal pattern of function and secretion. Likewise, abrupt discontinuation of anabolic steroid use can also result in withdrawal symptoms that can be dangerous and even potentially fatal.